The invention relates to a device for shaping sheared edges on stamped or fine-blanked workpieces such as bobs, disks, synchronizer rings for clutches or the like, having a burr, comprising an upper part and a lower part, which form at least one cutting stage for cutting the outer and/or inner contours of the workpiece, and at least one forming stage for mashing the burrs created during cutting, wherein the forming stage is divided into a fixed upper die part having an embossing be and a lower the part movable in the stroke direction having an embossing anvil.
The invention further relates to a method for shaping sheared edges of stamped or fine blanked-workpieces such as bobs, disks, synchronizer rings or the like, having a burr, in which the outer contour and/or inner contour of a workpiece are cut from a flat strip within a device comprising an upper part and a lower part in a stamping or fine blanking stage, the cut workpiece is transferred into a forming stage by a cross slide (16) after the device has been opened, and the net shape of the workpiece is created in this forming stage.
Stamped and fine-blanked parts are known to have a burr on the side of the sheared edge opposite the punch side, the size of the burr being dependent on various influencing factors, such as the die clearance between the punch and the die plate, the strength of the material, and the wear of the punch and cutting plate (see DIN 6930 and VDI Guideline 2906). This burr is undesirable since it limits the functional capability of high-precision parts. The burr must be removed by way of reworking, which necessitates additional complex work steps, such as grinding and brushing, for example, recutting (CH 665 367 A5) or mashing the burr edges (DE 41 13 165 A1, U.S. Pat. No. 3,478,558 A, DE 10 2004 020 483 A1, DE 10 2006 018 847 34).
The sheared edges of stamped parts additionally exhibit a variably large fracture surface, which considerably reduces the functional area, which is to say the flush-cut surface, so that in addition to removing the burr, it is also necessary to rework the entire sheared edge, losing material, so as to ensure a final contour of the part that is true to shape.
In particular in the case of parts having non-circular inner contours, such as kidney-shaped or elliptic openings, apertures or holes in the workpiece, reworking is particularly complex, since the subsequent mashing of the burr edges by way of roller bodies (DE 41 13 165, DE 10 2004 020 483 A1) is not suitable here, and only grinding and brushing of the cut edges will ensure the necessary precision.
Subsequent mashing of the burr has the added disadvantage that an embossing bead is formed, which detracts from the accuracy of the sheared edge.